The present invention relates to enabling and disabling circuitry of a cable modem connected to a cable network headend. More specifically, it relates to a headend disabling the receiver circuitry of a cable modem when it is determined that the cable modern is inactive and enabling the receiver circuitry of a cable modem when the cable modem is determined to be active by either a headend or the cable modem.
Cable modems connected to headends in a cable modem network typically lack power management schemes for disabling the receiver circuitry of a cable modem. Cable modems typically have transmitter enable and disable states that allow the transmitter circuitry of cable modems to power down when not in use. However, the receiver circuitry of cable modems has no such capability. DOCSIS 1.0 defines no capabilities for the headend to power down components such as the tuner, the demodulator, the CPU, and the DSP when the cable modem is not in use. Consequently, the cable network headend continually transmits messages to the cable modem and the cable modem, even when not in use by a client, processes these messages and continuously sends replies to the headend. DOCSIS 1.0 is described in “Data-Over-Cable Service Interface Specifications: Operations Support System Interface Specification RF Interface SP-OSSI-RF-I02-980410”, April 1998, the entirety of which is incorporated by reference for all purposes. The reply messages sent to the headend consume valuable upstream bandwidth.
Automatic timeouts for cable modems to power down are typically not used because of the difficulty of reactivating a cable modem. Manual power down schemes allow the user to disable the cable modem, but fail to allow the headend to enable the cable modem.
Currently available techniques for disabling and enabling receiver circuitry in a cable modem connected to a headend in a cable modem network have significant disadvantages with regard to saving power and preserving upstream bandwidth. It is therefore desirable to provide a system for disabling and enabling receiver circuitry of a cable modem connected to a headend in a cable modem network that exhibits desirable characteristics as well or better than the technologies discussed above.